multiconfig: add configs for FNG System and Yocto with Wayland

This is a first part of the fix for: https://secogroup.atlassian.net/browse/YT-89 (Initial steps to create a combined WIC with FnG System and Yocto)

Second part is available here: seco-ne/yocto/config!235 (merged)

In this MR, two multiconfigs were added:

• seconorth-fngsystem.conf: for building image of FNG System
• seconorth-wayland.conf: for building standard Yocto images

To enable and use these multiconfig:

1. Following lines need to be added to local.conf:

BBMULTICONFIG = "seconorth-fngsystem seconorth-wayland"

2. All dependency layers for both images/multiconfigs should be listed in bblayers.conf. For now, following lines should be present in bblayers.conf:

BBLAYERS += "${BSPDIR}/sources/meta-seconorth-nogplv3"
BBLAYERS += "${BSPDIR}/sources/meta-gplv2"

3. FNG System and Yocto Images should be built using following commands:

bitbake mc:seconorth-fngsystem:fngsystem-image
bitbake mc:seconorth-wayland:seconorth-image

Herewith both images can be build simultaneously.